Vibration occurs at 1500rpm, under crusing load at speed. Slight increase in throttle, goes away, slight decrease goes away. Get back to that maintain speed throttle position...vibration all over the place.

Harmonic balancer has slight wobble...very slight but noticable. Friend says motor mounts. Suggestions?

 

Car? Mods?

Do you have an aftermarket exhaust? This is usually the #1 cause of vibrations at a specific RPM (due to resonance).

 

My apologies...should have included that!

Stock 95 Z28.

 

where do you feel the vibration, in the steering wheel, pedals, console? I had a similar problem, turned out to be the driveshaft.. Could be a warped rotor, many things..

 

Try a few things. Try reving like that with the car sitting still. If you have a manual, also try in neutral with clutch in and out. Then put the rear up on jack stands and engage it and try reving the same way. Block the front tires unless you want to end up in the neighbors yard.

 

How many miles are on the car?

 

130k miles on the car. Vibes seem to be everywhere but the wheel.
Revving while parked (a4) doesn't produce the same results. There is a slight vibration but I can't get that earthquake going.

 

I'll put $20 down on U-Joints .....

Thomas.

 

I'm going with U-Joints or driveshaft needs to be balanced.

 

Strangely enough, this is my first RWD car and I said U or driveshaft initially.

Im replacing a few stock parts...I'll throw the harmonic balancer in just for ***** and giggles and if that doesn't solve the issue...def going with the driveshaft or U. Just wanted to get a consensus before I put all my eggs in one basket. Thanks guys! Love teh boards btw.

 

Whether your problem or not, no balancer should ever wobble.

 

Yeah...that's not good

 

I took a stab in the dark with my horrible vibrations and threw in a LS1 DS my buddy had for sale. Fixed it right up, however looking at the stock DS I was glad I swapped it before it was too late.

-Dustin-